Senator Bob Corker made the following statement at the hearing over the president's nuclear weapons authority:

“A number of members on both sides of the aisle, on and off the committee, have raised questions about the executive’s authorities with respect to war making, the use of nuclear weapons, and from a diplomatic perspective, entering into and terminating agreements with other countries.

“As I have mentioned publicly, this is one in a series of hearings where our committee will examine all of these issues. But today, it is my hope that we will remain focused on the topic at hand: the authority and the process for the use of nuclear weapons.

“The Congressional Research Service tells us this is the first time the foreign relations committee of the Senate or the House has met on this topic since 1976, 41 years ago.

“Making the decision to go to war of any sort is a heavy responsibility for our nation’s elected leaders. And the decision to use nuclear weapons is the most consequential of all.

“The Atomic Energy Act of 1946 and the subsequent practices recognize that the use of nuclear weapons must be subject to political control.

“This is why no general, or admiral, or defense secretary has the authority to order the use of nuclear weapons. Only the president – the elected political leader of the United States – has this authority.

“The nuclear arms race between the United States and the Soviet Union during the Cold War dramatically elevated the risk of nuclear conflict.

“As the Soviets developed massive numbers of nuclear weapons and the systems to deliver them to the United States, we planned for the unthinkable: how to get our missiles in the air within those few minutes before their warheads could hit us and possibly destroy our ability to respond.

“In that kind of scenario, there is no time for debate. Having such forces at the ready has been successful in deterring such an attack, and for that, we are grateful.

“But this process means the president has the sole authority to give that order, whether we are responding to a nuclear attack or not.

“Once that order is given and verified, there is no way to revoke it.

“To be clear, I would not support changes that would reduce our deterrence of adversaries or reassurance of our allies.

“But I would like to explore, as our predecessors in the House did 41 years ago, the realities of this system.

“I thank all of our distinguished witnesses, and the members of this committee, for the seriousness with which they approach the topic before us today, and I hope that together we can have a productive and enlightening discussion about this sober issue.

UPDATE (11:17 a.m.):

A former senior U.S. military officer says an order from the president to launch nuclear weapons can be refused if that command is determined to be illegal.

Retired Air Force Gen. Robert Kehler told the Senate Foreign Relations Committee on Tuesday the U.S. armed forces are obligated to follow legal orders, not illegal ones.

Kehler served as commander of Strategic Command from January 2011 to November 2013.

He says the legal principles of military necessity, distinction, and proportionality also apply to decisions about the use of nuclear weapons.

Sen. Ben Cardin of Maryland asked Kehler if that means the top officer at Strategic Command can deny the president's order if it fails those tests.

Kehler says, "Yes." But he says that would lead to a "very difficult conversation

UPDATE (10:30 a.m.)

Sen. Bob Corker, the Foreign Relations Committee chairman, says the panel's hearing on the president's authority to use nuclear weapons isn't a rebuke of President Donald Trump.

This is the first time in 41 years the committee is looking specifically at nuclear weapons use.

Trump over the weekend exchanged school-yard taunts with North Korea's Kim Jong Un. The provocative remarks and others by Trump aimed at Pyongyang have sparked concerns among lawmakers that he may be inciting a war with North Korea.

But Corker, a Tennessee Republican, says the session is one of a series to examine war making, the use of nuclear weapons, and conducting foreign policy overall.

He says, "This is not specific to anybody."

UPDATE: 10:15 a.m.

Senator Corker issued this opening statement at the start of the hearing:

“A number of members on both sides of the aisle, on and off the committee, have raised questions about the executive’s authorities with respect to war making, the use of nuclear weapons, and from a diplomatic perspective, entering into and terminating agreements with other countries.

“As I have mentioned publicly, this is one in a series of hearings where our committee will examine all of these issues. But today, it is my hope that we will remain focused on the topic at hand: the authority and the process for the use of nuclear weapons.

“The Congressional Research Service tells us this is the first time the foreign relations committee of the Senate or the House has met on this topic since 1976, 41 years ago.

“Making the decision to go to war of any sort is a heavy responsibility for our nation’s elected leaders. And the decision to use nuclear weapons is the most consequential of all.

“The Atomic Energy Act of 1946 and the subsequent practices recognize that the use of nuclear weapons must be subject to political control.

“This is why no general, or admiral, or defense secretary has the authority to order the use of nuclear weapons. Only the president – the elected political leader of the United States – has this authority.

“The nuclear arms race between the United States and the Soviet Union during the Cold War dramatically elevated the risk of nuclear conflict.

“As the Soviets developed massive numbers of nuclear weapons and the systems to deliver them to the United States, we planned for the unthinkable: how to get our missiles in the air within those few minutes before their warheads could hit us and possibly destroy our ability to respond.

“In that kind of scenario, there is no time for debate. Having such forces at the ready has been successful in deterring such an attack, and for that, we are grateful.

“But this process means the president has the sole authority to give that order, whether we are responding to a nuclear attack or not.

“Once that order is given and verified, there is no way to revoke it.

“To be clear, I would not support changes that would reduce our deterrence of adversaries or reassurance of our allies.

“But I would like to explore, as our predecessors in the House did 41 years ago, the realities of this system.

“I thank all of our distinguished witnesses, and the members of this committee, for the seriousness with which they approach the topic before us today, and I hope that together we can have a productive and enlightening discussion about this sober issue.

WASHINGTON (AP/WTVC) - Here's a question rarely raised before Donald Trump ran for the White House: If the president ordered a pre-emptive nuclear strike, could anyone stop him?

The answer is no.

Not the Congress. Not his secretary of defense. And by design, not the military officers who would be duty-bound to execute the order.

As Bruce Blair, a former nuclear missile launch officer and expert on nuclear command and control, has put it, "The protocol for ordering the use of nuclear weapons endows every president with civilization-ending power." Trump, he wrote in a Washington Post column last summer, "has unchecked authority to order a preventive nuclear strike against any nation he wants with a single verbal direction to the Pentagon war room."

Or, as then-Vice President Dick Cheney explained in December 2008, the president "could launch a kind of devastating attack the world's never seen. He doesn't have to check with anybody. He doesn't have to call the Congress. He doesn't have to check with the courts."

And the world has changed even more in the decade since, with North Korea posing a bigger and more immediate nuclear threat than had seemed possible. The nature of the U.S. political world has changed, too, and Trump's opponents — even within his own party — question whether he has too much power over nuclear weapons.

These realities will converge Tuesday in a Senate hearing room where the Foreign Relations Committee — headed by one of Trump's strongest Republican critics, Sen. Bob Corker of Tennessee — will hear testimony from a former commander of the Pentagon's nuclear war fighting command and other witnesses. The topic: "Authority to order the use of nuclear weapons."

Corker said numerous lawmakers have raised questions about legislative and presidential war-making authorities and the use of America's nuclear arsenal.

"This discussion is long overdue," Corker said in announcing the hearing.

Corker sent NewsChannel 9 a statement Tuesday morning in advance of the hearing:

“A number of members both on and off our committee have raised questions about the authorities of the legislative and executive branches with respect to war making, the use of nuclear weapons, and conducting foreign policy overall,” said Corker. “This continues a series of hearings to examine those issues and will be the first time since 1976 that this committee or our House counterparts have looked specifically at the authority and process for using U.S. nuclear weapons. This discussion is long overdue, and we look forward to examining this critical issue.”

Alex Wellerstein, a historian of science at the Stevens Institute of Technology who has researched and written extensively about presidential nuclear authority, said he hopes the discussion "might shed some more light on aspects of the procedures for presidential use of nuclear weapons that I think really needs to be known and talked about."

He said the U.S. system has evolved through tradition and precedent more than by laws.

"The technology of the bomb itself does not compel this sort of arrangement," he wrote in an email exchange. "This is a product of circumstances. I think the circumstances under which the system was created, and the world we now live in, are sufficiently different that we could, and perhaps should, contemplate revision of the system."

Asked about this Monday in an impromptu exchange at the Pentagon, Defense Secretary Jim Mattis was reluctant to describe his role in nuclear strike decision-making. "I'm the president's principal adviser on the use of force," he said. Asked whether he was comfortable with the system as it exists, he said, "I am," but did not elaborate.

Some aspects of presidential nuclear war-making powers are secret and therefore not well understood by the public. The system is built for fast decision-making, not debate. That's because speed is seen as essential in a crisis with a nuclear peer like Russia. Unlike North Korea, Russia has enough nuclear weapons to destroy the U.S. in minutes.

Russia's long-range missiles could reach the U.S. in about 30 minutes. Submarine-launched missiles fired from nearer U.S. shores might arrive in half that time. Given that some of the U.S. response time would be taken up by administrative steps, the president would have less than 10 minutes to absorb the information, review his options and make his decision, according to a December 2016 report by nuclear arms specialist Amy Woolf of the Congressional Research Service.

A president who decided to launch a nuclear attack — either in retaliation for a nuclear strike or in anticipation of one — would first hold an emergency conference with the defense secretary, the Joint Chiefs of Staff chairman and other advisers. The commander of U.S. Strategic Command, now Air Force Gen. John Hyten, would brief the president on strike options, and the president would make his decision.

The president would communicate his decision and transmit his authorization through a device called the nuclear football, a suitcase carried by a military aide. It's equipped with communication tools and a book with prepared war plans.

If the president decided to order a strike, he would identify himself to military officials at the Pentagon with codes unique to him. These codes are recorded on a card known as the biscuit that is carried by the president at all times. He would then transmit the launch order to the Pentagon and Strategic Command.

Blair, the former missile launch officer, said there is no way to reverse the president's order. And there would be no recalling missiles once launched.

Although fielded and assigned for use by the military, the nuclear bomb is inherently a political weapon, given its almost unimaginable destructive capacity. That explains why the system for controlling the use of U.S. nuclear weapons has been designed to concentrate decision-making power in the ultimate political office: the presidency.